A standard structural element for interior or exterior use comprises two like polygonal panels, normally of rectangular shape, that are mounted in a frame that holds them parallel to each other but at a modest spacing. The panels can be of glass for a Thermopane.TM. effect, in which case the space between them is filled with gas to act as insulation These panels can also be of dissimilar materials and thicknesses, although they are always of the same shape, and the space between them could be filled with any desired material depending on whether sound-deadening, insulating, conducting, or other effects were desired.
The standard frame for such an assembly is formed by a plurality of rails that are mitered at the corners to form a corner joint. Such rails can be made of extruded or otherwise profiled metal or plastic and invariably have two parallel but spaced grooves into which the respective side edges of the panels engage.
Accurately cutting and fitting these rails together is difficult, as is assembling them with the panels. Typically a glue or caulk is employed to secure the assembly together, entailing a messy step in the fabrication of such a panel assembly and making subsequent disassembly virtually impossible. Another disadvantage is that the frame thus formed is not particularly strong, so that mounting such a panel assembly for use as a sliding or pivoting door becomes fairly difficult, entailing the fastening of special hardware to the panels and rails at the corners.